If the letters of the word 'PROBABILITY' are written down at random in a row, then probability that two B's are together, is
A fair coin is tossed-at a fixed number of times. If the probability of getting exactly 3 heads equals the probability of getting exactly 5 heads, then the probability of getting exactly one head is
1/64
1/32
1/16
1/8
A person goes to office by car, scooter, bus and train, probability of which are 1/7, 3/7, 2/7 and 1/7, respectively. Probability that he reaches office late, if he takes car, scooter, bus or train is 2/9, 1/9, 4/9, and 1/9, respectively. Given that he reached office in time, the probability that he travelled by a car, is
1/7
2/7
3/7
4/7
Ram is visiting a friend. Ram knows that his friend has 2 children and 1 of them is a boy. Assuming that a child is equally likely to be a boy or a girl, then the probability that the other child is a girl, is
1/2
1/3
2/3
7/10
Out of 7 consonants and 4 vowels, the number of words (not necessarily meaningful) that can be made, each consisting of 3 consonants and 2 vowels is,
24800
25100
25200
25400
A fair six-faced die is rolled 12 times. The probability that each face turns up twice is equal to
A poker hand consists of 5 cards drawn at random from a well-shuffled pack of 52 cards. Then, the probability that a poker hand consists of a pair and a triple of equal face values (for example, 2 sevens and 3 kings or 2 aces and 3 queens, etc.) is
Each of a and b can take values 1 or 2 with equal probability. The probability that the equation ax2 + bx + 1= 0 has real roots, is equal to
Cards are drawn one-by-one without replacement from a well shuffled pack of 52 cards. Then, the probability that a face card (jack, queen or king) will appear for the first time on the third turn is equal to
C.
Ist turn Total number of face card = 12
Total number of elements in sample space, n(s) = 52
IInd turn P2 (no face card in second turn)
=
IIIrd turn P3 (face card in third turn)
=
There are two coins, one unbiased with probaility or getting heads and the other one is biased with probability of getting heads. A coin is selected at random and tossed. It shows heads up. Then, the probability that the unbiased coin was selected is